1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include "pthreadP.h"
#include <lowlevellock.h>
int
pthread_mutex_timedlock (
pthread_mutex_t *mutex,
const struct timespec *abstime)
{
pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
int result = 0;
/* We must not check ABSTIME here. If the thread does not block
abstime must not be checked for a valid value. */
switch (mutex->__data.__kind)
{
/* Recursive mutex. */
case PTHREAD_MUTEX_RECURSIVE_NP:
/* Check whether we already hold the mutex. */
if (mutex->__data.__owner == id)
{
/* Just bump the counter. */
if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
/* Overflow of the counter. */
return EAGAIN;
++mutex->__data.__count;
goto out;
}
else
{
/* We have to get the mutex. */
result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
if (result != 0)
goto out;
/* Only locked once so far. */
mutex->__data.__count = 1;
}
break;
/* Error checking mutex. */
case PTHREAD_MUTEX_ERRORCHECK_NP:
/* Check whether we already hold the mutex. */
if (mutex->__data.__owner == id)
return EDEADLK;
/* FALLTHROUGH */
default:
/* Correct code cannot set any other type. */
case PTHREAD_MUTEX_TIMED_NP:
simple:
/* Normal mutex. */
result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
break;
case PTHREAD_MUTEX_ADAPTIVE_NP:
if (! __is_smp)
goto simple;
if (lll_mutex_trylock (mutex->__data.__lock) != 0)
{
int cnt = 0;
int max_cnt = MIN (MAX_ADAPTIVE_COUNT,
mutex->__data.__spins * 2 + 10);
do
{
if (cnt++ >= max_cnt)
{
result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
break;
}
#ifdef BUSY_WAIT_NOP
BUSY_WAIT_NOP;
#endif
}
while (lll_mutex_trylock (mutex->__data.__lock) != 0);
mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8;
}
break;
}
if (result == 0)
{
/* Record the ownership. */
mutex->__data.__owner = id;
++mutex->__data.__nusers;
}
out:
return result;
}
|
